Astro Methods Index

Astro Methods Index

The Astro Methods is a collection of worksheets that solve problems of interest to the practicing amateur astronomer and serve as a learning tool to better understand the underlying phenomena at work. Several of the Methods employ the User Constants to create data and graphs customized to the user's time and place of observation.

The Methods demonstrate the utility of the Astro Functions as building blocks for complex astro-computing worksheets. For ease in following the logic, calculations are compartmentalized into reference worksheets inserted in the main worksheet. Interested users can open these fully documented reference sheets to study the Astro Functions and techniques employed. (Mathcad 8 Standard does not have the ability to hide sections of equations, hence the use of references to accomplish this.)

You are invited to extend the Methods to meet your personal needs by including them as reference sheets into your worksheets.

Julian and Gregorian Calendars

Here are notes on the problem of setting up a calendar system that is in synch with the position of the sun. The use of leap days to resolve this problem in the Julian calendar and the reforms that led to the Gregorian calendar are discussed. A practical example of -- and cautions concerning -- conversion between Julian and Gregorian dates is examined.

Sidereal Time for Civil Time

For any day this worksheet creates a handy chart to help the observer determine what part of the night sky is visible at any hour and location.

Polar Alignment with Polaris

This worksheet assists the observer in polar alignment of a telescope using the simple method of offsetting from Polaris. Graphs of Polaris in relation to the north celestial pole for the current and future times of interest are generated for your particular location.

Star and Planet Phenomena Charts

Get an idea of what is happening in the sky by using this sheet to generate customized low-precision charts of rise, transit and set phenomena of planetary bodies and stars for periods of a month to a year.

Earth's Nutation Visualized

Nutation is a slight wobble of the Earth that is in addition to that caused by precession. The slight affect this has on the location of the vernal equinox is used to determine such quantities as true obliquity, true equinox and apparent sidereal time. Various charts and a movie help you visualize this important phenomenon.